<?php

declare(strict_types=1);

namespace LayLink\Route;

use LayLink\Auth\PolicyChecker;
use LayLink\Node\NodeRegistry;

final class RouteResolver
{
    public function __construct(
        private readonly PolicyChecker $policyChecker,
        private readonly NodeRegistry $nodeRegistry,
    ) {
    }

    public function resolve(string $userId, string $host, int $port, string $protocol, ?string $routeHint): RouteDecision
    {
        $policy = $this->policyChecker->find($userId, $host, $port, $protocol);
        if ($policy === null) {
            return new RouteDecision(false, 'reject', null, null, 'policy_denied');
        }

        $routeType = (string)($policy['route_type'] ?? 'reject');
        $nodeId = $policy['node_id'] ?? null;
        if (($routeType === 'agent' || $routeType === 'border') && $protocol !== 'udp') {
            $nodeId = is_string($nodeId) && $nodeId !== '' ? $nodeId : $routeHint;
            if (!is_string($nodeId) || $nodeId === '') {
                return new RouteDecision(false, 'reject', null, (string)$policy['policy_id'], 'route_not_found');
            }
            if (!$this->nodeRegistry->isOnline($nodeId)) {
                return new RouteDecision(false, 'reject', $nodeId, (string)$policy['policy_id'], 'node_offline');
            }
        }

        return new RouteDecision(true, $routeType, $nodeId, (string)$policy['policy_id']);
    }
}